With the rapid development of computers, electronics and communication technologies, various wireless communication services using a wireless network have been provided. Accordingly, services provided by a mobile communication system using a wireless network are being developed into a multimedia communication service capable of transmitting data, such as circuit data and packet data, as well as voice.
With the recent development of information communication, International Mobile Telecommunication 2000 (IMT-2000) has been commercialized, which corresponds to the 3rd mobile communication system and has been established as a standard by the International Telecommunication Union Recommendation (ITU-R). The IMT-2000 includes a Code Division Multiple Access (CDMA) 2000 1X, 3X and Evolution Data Only (EV-DO), a wideband CDMA (wideband CDMA), etc., which can provide a wireless communication service by means of an IS-95C network evolved from the existing IS-95A network and IS-95B network.
In particular, the IMT-2000 is a mobile communication system which has been developed to implement worldwide direct roaming including personal mobility and service mobility, communication quality having the same level as that of a landline telephone, a high-speed packet data service, and various application services through the combination of a wired/wireless network. Such an IMT-2000 can provide various multimedia services, e.g., Audio On Demand (AOD), Video On Demand (VOD), etc., at higher speeds, as well as improving the quality of an existing voice and Wireless Application Protocol (WAP) service.
With the establishment of the Internet based on a Transmission Control Protocol/Internet Protocol (TCP/IP), systems enabling the user to search for various kinds of information and to transmit various data including characters, voice, images and moving pictures, in real time by means of the Internet are rapidly developed. Further, with such development, ultra-high-speed communication networks and so on are increasingly being introduced so as to enable users to use various communication services using the Internet in better environments.
Also, in order to provide a communication service without any spatial restriction, a wireless Internet service providing mobile communication subscribers with an Internet communication service through a wireless communication network has recently been proposed, and a large number of enterprises are progressing to develop a technique called wireless Internet. A wireless Internet service is an advanced personalization service based on the use of a terminal by an individual, and is characterized in that it is a service capable of providing specific information based on the user mobility. Mobile communication service subscribers may receive various kinds of information, such as news, weather, sports, stock, monetary circulation, exchange rates and traffic reports, through characters, voice, still images, moving images, etc.
Among various wireless Internet services using mobile stations, Location-Based Services (LBS) is in the spotlight due to its wide availability and convenience. The LBS represents a communication service for determining the location of a mobile station, such as a cellular phone or a Personal Digital Assistant (PDA), and providing supplementary information relating to the determined location. The LBS may be applied to various fields and situations, such as a rescue request, countermeasure for reporting of a crime, a Geographical Information System (GIS) for providing adjacent region information, traffic information, vehicle navigation and material flow control, and a location-based Customer Relationship Management (CRM).
In order to determine the location of a mobile station, the LBS has used either a method of understanding the location of a mobile station based on a Global Positioning System (GPS) and then detecting the location of the mobile station by means of navigation data which are measurement values of the GPS, or a method of understanding the location of a mobile station based on a base station or network. Meanwhile, a server for providing the LBS receives location information, which has been measured by a mobile station, via a mobile communication network including a Mobile Switching Center, and provides services based on the location of the corresponding user.
Meanwhile, only about 25% of mobile communication subscribers use a GPS-based location detecting method through mobile stations equipped with a GPS function, while the other mobile communication subscribers receive an LBS by using a Cell ID scheme based on a base station, which has a low accuracy in location detection. The Cell ID scheme causes an error up to a maximum of several kilometers, which acts as an obstacle in activation of the LBS.
Therefore, there is a need for providing a method of improving the accuracy of location detection for a mobile station not equipped with a GPS function, and a location-based service using such a method.